Radio-frequency identification (RFID) systems can use a number of readers and a number of tags to communicate utilizing various communication protocols. RFID tags can come in a large variety, including passive tags, active tags, and hybrid tags. Each of the various types of tags can use different power sources. For example, active tags can use a continuous power source such as a battery and respond to a low level initiation signal from a reader within a particular range and reply with a high frequency signal. The active tags can interact with readers of very long distances. The hybrid tags can use radio frequency energy to initiate interaction with a reader. The hybrid tags can use internal battery to interact with a reader. A passive tag can be entirely dependent on high level radio frequency energy from a particular reader to provide power for the passive tag's operation. The passive tag can be limited to operation when the passive tag is in contact and/or near contact with a reader. For example, the passive tag can be placed within an excitation field of the particular reader and the radio energy provided by the particular reader can be utilized by the passive tag to provide power to the passive tag and communicate with the particular reader.